I purchased this oximeter from its Australia distributor website in order to monitor my son's blood oxygen saturation when the hospital removed the equipment in his room. I was very nervous at the very beginning since the oximeter from the hospital catalog are well over $400. Fortunately, I was very pleased when I compared the oximetry readings on his finger while the hospital equipment was still hooked up, that both pieces of equipment provided the exact readings and change accordingly. Put my mind at ease.